PubAg

Main content area

You searched for: Journal Macromolecules Remove constraint Journal: Macromolecules Publication Year 2016 Remove constraint Publication Year: 2016 Source 2016 v.49 no.24 Remove constraint Source: 2016 v.49 no.24
Start Over

Search

41  Search Results

1 - 41 of 41
Number of results to display per page

Search Results

1. A 3D Simulation Investigation of the Influence of Temperature Increases on the Accuracy of Propagation Rate Coefficients Determined by Pulsed-Laser Polymerization

Author:
Nikitin, Anatoly N.; Lacík, Igor; Hutchinson, Robin A.
Source:
Macromolecules 2016 v.49 no.24 pp. 9320-9335
ISSN:
1520-5835
Subject:
molecular weight; polymerization; polymers; temperature profiles; vinyl acetate
Abstract:
... A numerical approach has been developed to capture the inhomogeneous and nonstationary processes of pulsed laser polymerization (PLP). The new simulation tool has been applied to systematically investigate how temperature gradients that develop in the sample cell influence the accuracy of propagation rate coefficients, kₚ, determined by the PLP-SEC method. Although the temperature in the center of ...
DOI:
10.1021/acs.macromol.6b02336

2. Alignment and Charge Transport of One-Dimensional Conjugated Polymer Nanowires in Insulating Polymer Blends

Author:
Chang, Mincheol; Su, Zhe; Egap, Eilaf
Source:
Macromolecules 2016 v.49 no.24 pp. 9449-9456
ISSN:
1520-5835
Subject:
coatings; nanocomposites; nanowires; polystyrenes
Abstract:
... Self-assembled and well-aligned nanowires (NWs) of poly(3-hexylthiophenes) (P3HT) embedded within insulating polystyrene (PS) matrix were found to have a high field-effect carrier mobility. We demonstrate that solution shear coating of P3HT-NWs/PS nanocomposites is an effective strategy in aligning P3HT NWs in the presence of PS and has a significant impact on the molecular order, morphology, and ...
DOI:
10.1021/acs.macromol.6b01721

3. A Molecular Thermodynamic Model of Complexation in Mixtures of Oppositely Charged Polyelectrolytes with Explicit Account of Charge Association/Dissociation

Author:
Salehi, Ali; Larson, Ronald G.
Source:
Macromolecules 2016 v.49 no.24 pp. 9706-9719
ISSN:
1520-5835
Subject:
Gibbs free energy; acidity; chemical reactions; dielectric properties; electrolytes; energy; mixing; salt concentration; thermodynamic models; titration
Abstract:
... Into an extended Voorn–Overbeek (EVO) free energy model of polyelectrolyte (PE) complexation and phase behavior, we incorporate three classes of short-ranged electrostatic effects, namely counterion association–dissociation, cross-chain ion pairing (IP), and charge regulation by treating each as a reversible chemical reaction leading to a corresponding law of mass action in a self-consistent fashi ...
DOI:
10.1021/acs.macromol.6b01464

4. Aqueous RAFT Photopolymerization with Oxygen Tolerance

Author:
Shanmugam, Sivaprakash; Xu, Jiangtao; Boyer, Cyrille
Source:
Macromolecules 2016 v.49 no.24 pp. 9345-9357
ISSN:
1520-5835
Subject:
air; ascorbic acid; molecular weight; oxygen; photocatalysts; polymerization; polymers; porphyrins; singlet oxygen; solvents; water solubility; zinc
Abstract:
... The emergence of light regulated controlled/living radical polymerization adds a new layer of control over polymerization. Light mediated polymerizations afford simple and facile route to modulate polymerization rate through manipulation of light intensity and by switching on/off the light source. Such mediation has resulted in the synthesis of 3D surfaces with both spatial and temporal control. H ...
DOI:
10.1021/acs.macromol.6b02060

5. Chain Exchange Kinetics in Diblock Copolymer Micelles in Ionic Liquids: The Role of χ

Author:
Ma, Yuanchi; Lodge, Timothy P.
Source:
Macromolecules 2016 v.49 no.24 pp. 9542-9552
ISSN:
1520-5835
Subject:
ambient temperature; composite polymers; energy; ionic liquids; micelles; neutron diffraction; polymethylmethacrylate
Abstract:
... Chain exchange kinetics of diblock copolymer micelles with lower critical micellization temperature (LCMT) phase behavior were investigated using time-resolved small-angle neutron scattering (TR-SANS). Three nearly identical isotopically substituted pairs of poly(methyl methacrylate)-block-poly(n-butyl methacrylate) (PMMA-b-PnBMA) diblocks were used in mixtures of the room temperature ionic liquid ...
DOI:
10.1021/acs.macromol.6b02212

6. Characterization of the Long-Range Internal Dynamics of Pyrene-Labeled Macromolecules by Pyrene Excimer Fluorescence

Author:
Farhangi, Shiva; Casier, Remi; Li, Lu; Thoma, Janine Lydia; Duhamel, Jean
Source:
Macromolecules 2016 v.49 no.24 pp. 9597-9604
ISSN:
1520-5835
Subject:
dimethyl sulfoxide; dimethylformamide; fluorescence; models; physical phenomena; solvents; tetrahydrofuran; toluene
Abstract:
... The long-range internal dynamics (LRID) of 74 pyrene-labeled macromolecules (PyLMs) were characterized in four solvents representing a broad range of dielectric constants equal to 2.4 (toluene), 7.6 (tetrahydrofuran, THF), 37.8 (N,N-dimethylformamide, DMF), and 46.7 (dimethyl sulfoxide, DMSO). The LRID of the PyLMs were quantified based on the parameters retrieved from the global model free analys ...
DOI:
10.1021/acs.macromol.6b02455

7. Chiroptical Properties of a Benzotriazole–Thiophene Copolymer Bearing Chiral Ethylhexyl Side Chains

Author:
Fronk, Stephanie L.; Shi, Yueqin; Siefrid, Martin; Mai, Cheng-Kang; McDowell, Caitlin; Bazan, Guillermo C.
Source:
Macromolecules 2016 v.49 no.24 pp. 9301-9308
ISSN:
1520-5835
Subject:
circular dichroism spectroscopy; composite polymers; dichlorobenzene; solids; solvents; thiophene; triazoles
Abstract:
... Conjugated polymers containing alternating thiophene units and benzotriazole structural units bearing either chiral (S)-2-ethylhexyl (PBTz-Th*) or racemic 2-ethylhexyl side chains (PBTz-Th) were synthesized. Characterization by optical absorption spectroscopy of both PBTz-Th* and its racemic counterpart reveal aggregated chains, even at dilute concentrations in good solvents. The presence of a chi ...
DOI:
10.1021/acs.macromol.6b02229

8. Comprehensive Study on Chain-End Transformation of Polymer–Iodides with Amines for Synthesizing Various Chain-End Functionalized Polymers

Author:
Chen, Chen; Xiao, Longqiang; Goto, Atsushi
Source:
Macromolecules 2016 v.49 no.24 pp. 9425-9440
ISSN:
1520-5835
Subject:
amines; desorption; matrix-assisted laser desorption-ionization mass spectrometry; moieties; polymethylmethacrylate; polystyrenes; reaction mechanisms
Abstract:
... Chain-end functionalized polymers (polymer–NHR) were successfully synthesized through the reaction of a polymer–iodide (polymer–I) with a primary amine (NH₂R), where the R moiety contains a functional group. This reaction was comprehensively studied for three different polymers, i.e., poly(butyl acrylate), polystyrene, and poly(methyl methacrylate), and six different functional amines with phenyl, ...
DOI:
10.1021/acs.macromol.6b02291

9. Crystalline Regio-/Stereoregular Glycine-Bearing Polymers from ROMP: Effect of Microstructures on Materials Performances

Author:
Li, Maosheng; Cui, Fengchao; Li, Yunqi; Tao, Youhua; Wang, Xianhong
Source:
Macromolecules 2016 v.49 no.24 pp. 9415-9424
ISSN:
1520-5835
Subject:
DNA; amino acids; biomimetic materials; biopolymers; catalysts; contact angle; crystallization; differential scanning calorimetry; hydrogen bonding; hydrophilicity; microstructure; polymerization; proteins; regioselectivity; stereochemistry; stereoselectivity; wide-angle X-ray scattering
Abstract:
... Synthesis of amino acid or peptide-bearing polymers with controlled microstructures is still a long-going challenge in polymer chemistry in contrast to natural biopolymers with exactly controlled microstructures like proteins and DNA. Here, a series of new glycine-substituted cyclooctenes monomers were designed and synthesized. Ring-opening metathesis polymerizations (ROMP) of all 3-substituted mo ...
DOI:
10.1021/acs.macromol.6b02244

10. Effects of Molecular Weight below the Entanglement Threshold on Interfacial Nanoparticles/Polymer Dynamics

Author:
Klonos, Panagiotis; Kulyk, Kostiantyn; Borysenko, Mykola V.; Gun’ko, Vladimir M.; Kyritsis, Apostolos; Pissis, Polycarpos
Source:
Macromolecules 2016 v.49 no.24 pp. 9457-9473
ISSN:
1520-5835
Subject:
dielectric spectroscopy; differential scanning calorimetry; models; molecular dynamics; molecular weight; nanoparticles; polydimethylsiloxane; silica
Abstract:
... This work deals with effects of polymer molecular weight, Wₘ, below the entanglement threshold, Wₘ,ₑ, on molecular dynamics of polydimethylsiloxane (PDMS) adsorbed onto silica particles, employing differential scanning calorimetry (DSC) and two dielectric techniques: broadband dielectric spectroscopy (BDS) and thermally stimulated depolarization currents (TSDC). The rigid amorphous polymer fractio ...
DOI:
10.1021/acs.macromol.6b01931

11. Emitting Species of Poly(3-hexylthiophene): From Single, Isolated Chains to Bulk

Author:
Raithel, Dominic; Baderschneider, Sebastian; de Queiroz, Thiago B.; Lohwasser, Ruth; Köhler, Jürgen; Thelakkat, Mukundan; Kümmel, Stephan; Hildner, Richard
Source:
Macromolecules 2016 v.49 no.24 pp. 9553-9560
ISSN:
1520-5835
Subject:
density functional theory; energy; molecular weight; photoluminescence; spectroscopy
Abstract:
... The photophysical properties of films of alkyl-substituted polythiophenes are governed by a subtle interplay between intra- and interchain electronic couplings. The intramolecular properties, however, are still not entirely clear because polythiophenes possess a strong tendency to form π-stacked aggregate structures with appreciable interchain couplings. Here we employ low-temperature single-molec ...
DOI:
10.1021/acs.macromol.6b02077

12. Employing a Sugar-Derived Dimethacrylate to Evaluate Controlled Branch Growth during Polymerization with Multiolefinic Compounds

Author:
Pal, Sunirmal; Brooks, William L. A.; Dobbins, Daniel J.; Sumerlin, Brent S.
Source:
Macromolecules 2016 v.49 no.24 pp. 9396-9405
ISSN:
1520-5835
Subject:
chemical structure; copolymerization; molecular weight; polyethylene glycol
Abstract:
... Radical copolymerization of divinyl monomers in the presence of chain transfer agents leads to soluble hyperbranched polymers. In this work, hyperbranched poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMA) with degradable cross-linker branch points derived from glucarodilactone methacrylate was prepared via reversible addition–fragmentation chain transfer (RAFT) polymerization to provi ...
DOI:
10.1021/acs.macromol.6b02079

13. End-Capping Strategies for Triggering End-to-End Depolymerization of Polyglyoxylates

Author:
Fan, Bo; Trant, John F.; Gillies, Elizabeth R.
Source:
Macromolecules 2016 v.49 no.24 pp. 9309-9319
ISSN:
1520-5835
Subject:
coatings; depolymerization; drugs; moieties; molecular weight; plastics
Abstract:
... Polymers that undergo end-to-end depolymerization in response to the cleavage of a stimuli-responsive end-cap are promising for diverse applications from drug delivery to responsive coatings and plastics. It is critical that the end-cap is designed to respond to an appropriate stimulus for the application. In the current work, end-caps for triggering the depolymerization of poly(ethyl glyoxylate) ...
DOI:
10.1021/acs.macromol.6b02320

14. Enhanced Crystallinity of Polymer Nanofibers without Loss of Nanofibrous Morphology via Heterogeneous Photothermal Annealing

Author:
Viswanath, Vidya; Maity, Somsubhra; Bochinski, Jason R.; Clarke, Laura I.; Gorga, Russell E.
Source:
Macromolecules 2016 v.49 no.24 pp. 9484-9492
ISSN:
1520-5835
Subject:
annealing; crystal structure; crystallites; crystallization; energy; heat; nanofibers; nanogold; nanoparticles; polyethylene glycol; porosity; temperature
Abstract:
... Poly(ethylene oxide) electrospun nanofibers with a low concentration of embedded gold nanoparticles (AuNP) were subjected to postfabrication annealing via photothermal heating from the nanoparticles. The results, including nanofibrous mat morphology, crystallinity fraction as a function of annealing time and modality, and average crystallite size, were compared with that for conventional heating a ...
DOI:
10.1021/acs.macromol.6b01655

15. Entangled Linear Polymer Solutions at High Shear: From Strain Softening to Hardening

Author:
Liu, Gengxin; Wang, Shi-Qing
Source:
Macromolecules 2016 v.49 no.24 pp. 9647-9654
ISSN:
1520-5835
Subject:
glass transition temperature; polymethylmethacrylate; polystyrenes
Abstract:
... The present rheological study reveals for the first time that entangled polymer solutions made of linear polystyrene or poly(methyl methacrylate) can exhibit strain hardening due to non-Gaussian stretching during startup shear at sufficiently high rates and temperatures well above their overall glass transition temperatures: Tg,ₛₒₗᵤₜₑ > Tₑₓₚ > Tg,ₛₒₗᵤₜᵢₒₙ. The solutions made of high-Tg polymers on ...
DOI:
10.1021/acs.macromol.6b02053

16. Fabrication of Liquid Protrusions on Non-Cross-Linked Colloidal Particles for Shape-Controlled Patchy Microparticles

Author:
Tian, Lei; Li, Xue; Zhao, Panpan; Ali, Zafar; Zhang, Qiuyu
Source:
Macromolecules 2016 v.49 no.24 pp. 9626-9636
ISSN:
1520-5835
Subject:
absorption; coatings; colloids; emulsions; liquids; microparticles; models; oils; polymerization; polystyrenes; thermodynamics
Abstract:
... The use of single particles as building blocks for the design and construction of advanced materials is generally recognized as a promising approach. This paper reports a novel double-speed swelling (DSS) technique to fabricate solid–liquid asymmetric monomer-swollen particles (MSPs) with adjustable and removable liquid protrusions on the surface of non-cross-linked poly(glycidyl methacrylate) (PG ...
DOI:
10.1021/acs.macromol.6b02059

17. High Charge Density Coacervate Assembly via Hybrid Monte Carlo Single Chain in Mean Field Theory

Author:
Lytle, Tyler K.; Radhakrishna, Mithun; Sing, Charles E.
Source:
Macromolecules 2016 v.49 no.24 pp. 9693-9705
ISSN:
1520-5835
Subject:
DNA; Gibbs free energy; Monte Carlo method; aqueous solutions; biopolymers; electrolytes; electrostatic interactions; heparin; ionic strength; mathematical theory; models; pH; polyacrylic acid; separation; temperature
Abstract:
... Oppositely charged polyelectrolytes in aqueous solution can undergo associative phase separation into a liquid-like complex coacervate phase that is polyelectrolyte-rich and an aqueous supernatant phase that is polyelectrolyte-deficient. This same complex coacervation motif can be used to drive self-assembly of block copolyelectrolytes via electrostatic interactions and can be controlled using e.g ...
DOI:
10.1021/acs.macromol.6b02159

18. Influence of Anion Hydrophilicity on the Conformation of a Hydrophobic Weak Polyelectrolyte Brush

Author:
Murdoch, Timothy J.; Willott, Joshua D.; de Vos, Wiebe M.; Nelson, Andrew; Prescott, Stuart W.; Wanless, Erica J.; Webber, Grant B.
Source:
Macromolecules 2016 v.49 no.24 pp. 9605-9617
ISSN:
1520-5835
Subject:
acetates; aqueous solutions; electrolytes; hydrophilicity; hydrophobicity; ionic strength; pH; polymers; potassium; potassium nitrate; reflectometry; thiocyanates
Abstract:
... The conformation of a hydrophobic, weak cationic poly(2-diisopropylamino)ethyl methacrylate (PDPA) brush was studied using neutron reflectometry as a function of aqueous solution pH, ionic strength, and anion identity. In pH 4, 10 mM potassium nitrate the brush is highly charged, resulting in an extended, dilute conformation; at pH 9 the uncharged brush collapses to a single, dense layer. The brus ...
DOI:
10.1021/acs.macromol.6b01897

19. Mechanical Properties of Star Block Polymer Thermoplastic Elastomers with Glassy and Crystalline End Blocks

Author:
Burns, Adam B.; Register, Richard A.
Source:
Macromolecules 2016 v.49 no.24 pp. 9521-9530
ISSN:
1520-5835
Subject:
ambient temperature; crosslinking; crystallites; differential scanning calorimetry; hysteresis; mechanical properties; plastic deformation; small-angle X-ray scattering; thermoplastics
Abstract:
... The mechanical properties of thermoplastic elastomers (TPEs) consisting of 6-arm star block polymers with glassy, crystalline, or composite crystalline–glassy physical cross-linking (hard) domains were investigated and compared to the analogous linear triblock or pentablock polymers. The 6-arm stars exhibited qualitatively similar solid-state morphologies and phase behavior to their linear counter ...
DOI:
10.1021/acs.macromol.6b02175

20. Medium-Bandgap Conjugated Polymers Containing Fused Dithienobenzochalcogenadiazoles: Chalcogen Atom Effects on Organic Photovoltaics

Author:
Lee, Jaewon; Sin, Dong Hun; Clement, J. Arul; Kulshreshtha, Chandramouli; Kim, Heung Gyu; Song, Eunjoo; Shin, Jisoo; Hwang, Hyeongjin; Cho, Kilwon
Source:
Macromolecules 2016 v.49 no.24 pp. 9358-9370
ISSN:
1520-5835
Subject:
polymers; solar cells; solar energy
Abstract:
... We designed, synthesized, and characterized a series of three medium-bandgap conjugated polymers (PBDTfDTBO, PBDTfDTBT, and PBDTfDTBS) consisting of fused dithienobenzochalcogenadiazole (fDTBX)-based weak electron-deficient and planar building blocks, which possess bandgaps of ∼2.01 eV. The fDTBX-based medium-bandgap polymers exhibit deep-lying HOMO levels (∼5.51 eV), which is beneficial for use i ...
DOI:
10.1021/acs.macromol.6b01569

21. Metal-Coordination Complexes Mediated Physical Hydrogels with High Toughness, Stick–Slip Tearing Behavior, and Good Processability

Author:
Zheng, Si Yu; Ding, Hongyao; Qian, Jin; Yin, Jun; Wu, Zi Liang; Song, Yihu; Zheng, Qiang
Source:
Macromolecules 2016 v.49 no.24 pp. 9637-9646
ISSN:
1520-5835
Subject:
composite polymers; coordination compounds; crosslinking; energy; hydrogels; mechanical properties; pH
Abstract:
... It is challenging to develop hydrogels with a combination of excellent mechanical properties, versatile functions, and good processability. Here we report a physical hydrogel of poly(acrylamide-co-acrylic acid) (P(AAm-co-AAc)) cross-linked by carboxyl–Fe³⁺ coordination complexes that possesses high stiffness and toughness, fatigue resistance, and stimulation-triggered healing along with shape memo ...
DOI:
10.1021/acs.macromol.6b02150

22. Model-Based Design To Push the Boundaries of Sequence Control

Author:
Fierens, Stijn K.; Telitel, Sofia; Van Steenberge, Paul H. M.; Reyniers, Marie-Françoise; Marin, Guy B.; Lutz, Jean-François; D’hooge, Dagmar R.
Source:
Macromolecules 2016 v.49 no.24 pp. 9336-9344
ISSN:
1520-5835
Subject:
Monte Carlo method; composite polymers; polymerization; product quality; styrene
Abstract:
... An innovative model-based design strategy to synthesize well-defined sequence-controlled polymers is presented, enabling selection of both the most appropriate mediating agent and reaction conditions. In combination with experimental analysis, advanced kinetic Monte Carlo simulations are conducted, allowing a visualization of the connectivity of all monomer units of ca. 10⁵ individual copolymer ch ...
DOI:
10.1021/acs.macromol.6b01699

23. Molecular Processes Leading to “Necking” in Extensional Flow of Polymer Solutions: Using Microfluidics and Single DNA Imaging

Author:
Sachdev, Shaurya; Muralidharan, Aswin; Boukany, Pouyan E.
Source:
Macromolecules 2016 v.49 no.24 pp. 9578-9585
ISSN:
1520-5835
Subject:
DNA; droplets; fluorescence microscopy; image analysis; liquids; polyacrylamide
Abstract:
... We study the necking and pinch-off dynamics of liquid droplets that contain a semidilute polymer solution of polyacrylamide close to overlap concentration by combining microfluidics and single DNA observation. Polymeric droplets are stretched by passing them through the stagnation point of a T-shaped microfluidic junction. In contrast with the sudden breakup of Newtonian droplets, a stable neck is ...
DOI:
10.1021/acs.macromol.6b01755
PubMed:
28216791
PubMed Central:
PMC5312824

24. Multicomponent Tandem Polymerizations of Aromatic Diynes, Terephthaloyl Chloride, and Hydrazines toward Functional Conjugated Polypyrazoles

Author:
Tang, Xiaojuan; Zheng, Chao; Chen, Yizhao; Zhao, Zujin; Qin, Anjun; Hu, Rongrong; Tang, Ben Zhong
Source:
Macromolecules 2016 v.49 no.24 pp. 9291-9300
ISSN:
1520-5835
Subject:
alkynes; ambient temperature; chlorides; hydrazine; luminescence; molecular weight; nuclear magnetic resonance spectroscopy; polymerization; polymers; scientists; solubility; thermal stability
Abstract:
... Multicomponent tandem polymerizations (MCTPs) of alkynes enjoying concise procedure, operational simplicity, synthetic efficiency, large structural diversity, high atom economy, and environmental benefit are recently developed as efficient strategies to synthesize functional conjugated polymers, which have attracted much attention from polymer scientists. In this work, through combination of Sonog ...
DOI:
10.1021/acs.macromol.6b02192

25. Multiple Chain Packing and Phase Composition in Regioregular Poly(3-butylthiophene) Films

Author:
Yuan, Yuan; Shu, Jie; Kolman, Krzysztof; Kiersnowski, Adam; Bubeck, Christoph; Zhang, Jianming; Hansen, Michael Ryan
Source:
Macromolecules 2016 v.49 no.24 pp. 9493-9506
ISSN:
1520-5835
Subject:
Fourier transform infrared spectroscopy; films (materials); nuclear magnetic resonance spectroscopy; polymers; thiophene; wide-angle X-ray scattering
Abstract:
... On the basis of different film preparation conditions, we address the phase composition and thiophene main-chain and butyl side-chain organization of three regioregular poly(3-butylthiophene) (P3BT) samples prepared by drop-casting. These samples are readily identified by wide-angle X-ray diffraction (WAXD) with the structural P3BT polymorphs commonly referred to as forms I, I′, and II. Here, we s ...
DOI:
10.1021/acs.macromol.6b01828

26. Nonuniversal Coupling of Cage Scale Hopping and Collective Elastic Distortion as the Origin of Dynamic Fragility Diversity in Glass-Forming Polymer Liquids

Author:
Xie, Shi-Jie; Schweizer, Kenneth S.
Source:
Macromolecules 2016 v.49 no.24 pp. 9655-9664
ISSN:
1520-5835
Subject:
melting; polyethylene; polypropylenes; temperature; vitrification
Abstract:
... We formulate a theoretical mechanism for the physical origin of the massive dynamic fragility range observed in long chain glass-forming polymer melts within the context of the force-level elastically collective nonlinear Langevin equation theory of coupled local–nonlocal activated segmental relaxation. The hypothesis involves how the cage scale barrier hopping process on the three Kuhn segment le ...
DOI:
10.1021/acs.macromol.6b02272

27. On-Demand Visible Light Activated Amine/Benzoyl Peroxide Redox Initiating Systems: A Unique Tool To Overcome the Shadow Areas in Photopolymerization Processes

Author:
Garra, P.; Morlet-Savary, F.; Dietlin, C.; Fouassier, J. P.; Lalevée, J.
Source:
Macromolecules 2016 v.49 no.24 pp. 9371-9381
ISSN:
1520-5835
Subject:
Fourier transform infrared spectroscopy; air; free radicals; nuclear magnetic resonance spectroscopy; phosphine; phosphorus; photolysis; polymerization; polymers; stable isotopes; ultraviolet-visible spectroscopy
Abstract:
... A novel way to counterbalance the drawbacks and advantages of photopolymerization and redox polymerization is proposed. Photoinitiating systems based on charge transfer complexes (CTC) between a phosphine and an iodonium salt as well as an amine and iodonium salt are checked for the free radical polymerization of methacrylates. Polymer materials as thick as 8.5 cm can be produced under air upon ex ...
DOI:
10.1021/acs.macromol.6b02167

28. PCDTBT: From Polymer Photovoltaics to Light-Emitting Diodes by Side-Chain-Controlled Luminescence

Author:
Lombeck, Florian; Di, Dawei; Yang, Le; Meraldi, Lorenzo; Athanasopoulos, Stavros; Credgington, Dan; Sommer, Michael; Friend, Richard H.
Source:
Macromolecules 2016 v.49 no.24 pp. 9382-9387
ISSN:
1520-5835
Subject:
absorption; composite polymers; electrochemiluminescence; light emitting diodes; solar energy; solubility
Abstract:
... Poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole) (PCDTBT) is a copolymer composed of alternating thiophene–benzothiadiazole–thiophene (TBT) and carbazole (Cbz) repeat units widely used for stable organic photovoltaics. However, the solubility of PCDTBT is limited, which decreases polymer yield and makes synthesis and purification tedious. Here, we introdu ...
DOI:
10.1021/acs.macromol.6b02216

29. Periodic Surface Undulation in Cholesteric Liquid Crystal Elastomers

Author:
Nagai, Hama; Liang, Xiaobin; Nishikawa, Yukihiro; Nakajima, Ken; Urayama, Kenji
Source:
Macromolecules 2016 v.49 no.24 pp. 9561-9567
ISSN:
1520-5835
Subject:
deformation; liquid crystals; temperature
Abstract:
... Cholesteric liquid crystal elastomer (CLCE) films, whose helical axis is parallel to a direction in the film plane, exhibit a periodic surface undulation with a period corresponding to a half-pitch (about 100 μm) of the helical director configuration. Temperature variation drives not only a finite macroscopic uniaxial deformation along the helical axis but also a marked variation in the surface un ...
DOI:
10.1021/acs.macromol.6b01688

30. Poly(1-adamantyl acrylate): Living Anionic Polymerization, Block Copolymerization, and Thermal Properties

Author:
Lu, Wei; Huang, Caili; Hong, Kunlun; Kang, Nam-Goo; Mays, Jimmy W.
Source:
Macromolecules 2016 v.49 no.24 pp. 9406-9414
ISSN:
1520-5835
Subject:
acrylates; anions; composite polymers; copolymerization; glass transition temperature; ligands; lithium chloride; molecular weight; sodium; strength (mechanics); tetrahydrofuran; thermal stability; thermoplastics
Abstract:
... Living anionic polymerization of acrylates is challenging due to intrinsic side reactions including backbiting reactions of propagating enolate anions and aggregation of active chain ends. In this study, the controlled synthesis of poly(1-adamatyl acrylate) (PAdA) was performed successfully for the first time via living anionic polymerization through investigation of the initiation systems of sec- ...
DOI:
10.1021/acs.macromol.6b01732

31. Polydisperse Polymer Brushes: Internal Structure, Critical Behavior, and Interaction with Flow

Author:
Qi, Shuanhu; Klushin, Leonid I.; Skvortsov, Alexander M.; Schmid, Friederike
Source:
Macromolecules 2016 v.49 no.24 pp. 9665-9683
ISSN:
1520-5835
Subject:
Monte Carlo method; brushes; hydrodynamics; polymers
Abstract:
... We study the effect of polydispersity on the structure of polymer brushes by analytical theory, a numerical self-consistent field approach, and Monte Carlo simulations. The polydispersity is represented by the Schulz–Zimm chain-length distribution. We specifically focus on three different polydispersities representing sharp, moderate, and extremely wide chain length distributions and derive explic ...
DOI:
10.1021/acs.macromol.6b02026

32. Polymer-Fe3O4 Composite Janus Nanoparticles

Author:
Yao, Xiaohui; Jing, Jingyun; Liang, Fuxin; Yang, Zhenzhong
Source:
Macromolecules 2016 v.49 no.24 pp. 9618-9625
ISSN:
1520-5835
Subject:
Janus; hydrophobicity; iron oxides; magnetism; nanoparticles; polymers; temperature
Abstract:
... A Fe₃O₄ nanoparticle (NP) based on composite Janus NP with single polymer chain is prepared by termination of the modified Fe₃O₄ NP with the anionic living polymer chain. The requisite that the polymer chain should be sufficiently large over the NP diameter determines the grafting of single polymer chain. From the opposite side of the NP surface, functional species can be selectively grown for exa ...
DOI:
10.1021/acs.macromol.6b02004

33. Predicting the Macroscopic Fracture Energy of Epoxy Resins from Atomistic Molecular Simulations

Author:
Meng, Zhaoxu; Bessa, Miguel A.; Xia, Wenjie; Kam Liu, Wing; Keten, Sinan
Source:
Macromolecules 2016 v.49 no.24 pp. 9474-9483
ISSN:
1520-5835
Subject:
crosslinking; energy; epoxides; mechanics; molecular dynamics; polymers; prediction; resins; simulation models
Abstract:
... Predicting the macroscopic fracture energy of highly cross-linked glassy polymers from atomistic simulations is challenging due to the size of the process zone being large in these systems. Here, we present a scale-bridging approach that links atomistic molecular dynamics simulations to macroscopic fracture properties on the basis of a continuum fracture mechanics model for two different epoxy mat ...
DOI:
10.1021/acs.macromol.6b01508

34. Salting-Out and Salting-In of Polyelectrolyte Solutions: A Liquid-State Theory Study

Author:
Zhang, Pengfei; Alsaifi, Nayef M.; Wu, Jianzhong; Wang, Zhen-Gang
Source:
Macromolecules 2016 v.49 no.24 pp. 9720-9730
ISSN:
1520-5835
Subject:
Gibbs free energy; electrolytes; energy; entropy; equations; mathematical theory; physical phases; salt concentration; separation
Abstract:
... We study the phase behavior of polyelectrolyte (PE) solutions with salt using a simple liquid-state (LS) theory. This LS theory accounts for hard-core excluded volume repulsion by the Boublik–Mansoori–Carnahan–Starling–Leland equation of state, electrostatic correlation by the mean-spherical approximation, and chain connectivity by the first-order thermodynamic perturbation theory. We predict a cl ...
DOI:
10.1021/acs.macromol.6b02160

35. Scrolled/Flat Crystalline Structures of Poly(3-hexylthiophene) and Poly(ethylene glycol) Block Copolymers Subsuming Unseeded Half-Ring-Like and Seeded Cubic, Epitaxial, and Fibrillar Crystals

Author:
Agbolaghi, Samira; Zenoozi, Sahar; Hosseini, Zahra; Abbasi, Farhang
Source:
Macromolecules 2016 v.49 no.24 pp. 9531-9541
ISSN:
1520-5835
Subject:
anisotropy; composite polymers; crystal structure; crystallization; crystals; polyethylene glycol; prisms
Abstract:
... Three distinct types of poly(3-hexylthiophene) (P3HT)-based crystals were developed using unseeded and seeded protocols. First, unseeded flat fibrillar and scrolled half-ring-like crystals were prepared by isothermal crystallization of homo-P3HT and P3HT-b-poly(ethylene glycol) (PEG) block copolymers. Anisotropic accumulation of grafted coily PEG blocks on the opposite surfaces of P3HT half-rings ...
DOI:
10.1021/acs.macromol.6b02295

36. Suppression of Homocoupling Side Reactions in Direct Arylation Polycondensation for Producing High Performance OPV Materials

Author:
Kuwabara, Junpei; Fujie, Yohei; Maruyama, Keisuke; Yasuda, Takeshi; Kanbara, Takaki
Source:
Macromolecules 2016 v.49 no.24 pp. 9388-9395
ISSN:
1520-5835
Subject:
arylation; condensation reactions; polymers; solid phase extraction; toluene
Abstract:
... Suppression of side reactions in C–H direct arylation polycondensation is important for developing this method as a reliable synthetic tool for conjugated polymer materials. To find appropriate reaction conditions for avoiding homocoupling side reactions, two types of reaction conditions were investigated: the direct arylation of electron-rich C–H monomers in N,N-dimethylacetamide (DMAc system) an ...
DOI:
10.1021/acs.macromol.6b02380

37. Synergistic Toughening of Epoxy Modified by Graphene and Block Copolymer Micelles

Author:
Li, Tuoqi; He, Siyao; Stein, Andreas; Francis, Lorraine F.; Bates, Frank S.
Source:
Macromolecules 2016 v.49 no.24 pp. 9507-9520
ISSN:
1520-5835
Subject:
composite polymers; crosslinking; energy; epoxides; gibberellic acid; graphene; graphene oxide; micelles; mixing; molecular weight; polyethylene glycol; scanning electron microscopes; scanning electron microscopy; synergism; topology; transmission electron microscopy
Abstract:
... Binary composites formed by individually mixing exfoliated graphene oxide modified with amine-terminated poly(butadiene–acrylonitrile) (GA) and a spherical micelle forming poly(ethylene oxide)-b-poly(ethylene-alt-propylene) (OP) diblock copolymer with a thermoset epoxy, and the associated GA/OP/epoxy ternary composites, were prepared and studied as a function of the molecular weight Mc between cro ...
DOI:
10.1021/acs.macromol.6b01964

38. Synthesis and Properties of Polycarbosilanes Having 5-Membered Cyclic Carbonate Groups as Solid Polymer Electrolytes

Author:
Matsumoto, Kozo; Kakehashi, Miho; Ouchi, Hirotaka; Yuasa, Masayoshi; Endo, Takeshi
Source:
Macromolecules 2016 v.49 no.24 pp. 9441-9448
ISSN:
1520-5835
Subject:
ambient temperature; cations; differential scanning calorimetry; glass transition temperature; lithium; moieties; polymerization; polymers
Abstract:
... We conducted ring-opening polymerization of silacyclobutane monomers 1-[2-(2,4-dioxa-3-pentanoyl)ethyl]-1-methylsilacyclobutane (SBMC) and 1,1-di[2-(2,4-dioxa-3-pentanoyl)ethyl]silacyclobutane (SBDC) to obtain polySBMC and polySBDC, respectively, and measured their ionic conductivity with addition of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) or lithium trifluoromethanesulfonate (LiOTf). ...
DOI:
10.1021/acs.macromol.6b01516

39. Synthesis of Hybrid Silica Nanoparticles Densely Grafted with Thermo and pH Dual-Responsive Brushes via Surface-Initiated ATRP

Author:
Wu, Lei; Glebe, Ulrich; Böker, Alexander
Source:
Macromolecules 2016 v.49 no.24 pp. 9586-9596
ISSN:
1520-5835
Subject:
aqueous solutions; brushes; composite polymers; dispersibility; halogens; methyl iodide; nanoparticles; organoiodine compounds; pH; polymerization; silica
Abstract:
... This work introduces a synthesis of well-defined thermo and pH dual-responsive poly(N-isopropylacrylamide)-b-poly(4-vinylpyridine)-grafted silica nanoparticles (SNPs-g-PNIPAM-b-P4VP) via surface-initiated atom transfer radical polymerization (ATRP). ATRP initiators were attached onto the surfaces of silica nanoparticles followed by ATRP of N-isopropylacrylamide (NIPAM). During the surface-initiate ...
DOI:
10.1021/acs.macromol.6b01792

40. Thermoresponsive Toughening in LCST-Type Hydrogels: Comparison between Semi-Interpenetrated and Grafted Networks

Author:
Guo, Hui; Sanson, Nicolas; Marcellan, Alba; Hourdet, Dominique
Source:
Macromolecules 2016 v.49 no.24 pp. 9568-9577
ISSN:
1520-5835
Subject:
calorimetry; crosslinking; deformation; energy; hydrogels; hydrophilicity; mechanical properties; modulus of elasticity; neutron diffraction; phase transition; polymers; temperature; topology
Abstract:
... Hydrophilic and LCST polymer chains, poly(N,N-dimethylacrylamide) (PDMA) and poly(N-isopropylacrylamide) (PNIPA), were combined in semi-interpenetrated architectures to investigate their responsive properties in swollen isochoric conditions comparatively to grafted network structures. Using equal weight fractions of PDMA and PNIPA, semi-IPN designed with opposite topologies have demonstrated a the ...
DOI:
10.1021/acs.macromol.6b02188

41. Using Theory and Simulations To Calculate Effective Interactions in Polymer Nanocomposites with Polymer-Grafted Nanoparticles

Author:
Martin, Tyler B.; Jayaraman, Arthi
Source:
Macromolecules 2016 v.49 no.24 pp. 9684-9692
ISSN:
1520-5835
Subject:
models; nanoparticles; polymer nanocomposites; polymers; thermodynamics
Abstract:
... Using theory and large-scale simulations, we demonstrate how one can program structure and thermodynamics into polymer-grafted particles filled polymer nanocomposites (PNCs). We simulate varying graft (G) and matrix (M) polymer compositions for varying model graft–matrix bead pairwise interactions, χGM, and calculate structural features and the effective graft–matrix interaction parameter, χGMᵉᶠᶠ, ...
DOI:
10.1021/acs.macromol.6b01920